As one of general therapies for cancer, there is chemotherapy. In chemotherapy, various kinds of anticancer agents are administered. However, effective anticancer agents vary depending on the type of cancer and patient's individual difference. Further, there are many cases wherein an anticancer agent, there is overlap between therapeutic range and maleficent range. Accordingly, there is a danger that the possibility of cancer recurrence is increased when an ineffective anticancer agent is administered. In addition, a patient's strength is lowered by administration of an ineffective anticancer agent. Therefore, there is a danger that even if another effective anticancer agent is then administered to the patient, its efficacy cannot be sufficiently demonstrated. From the foregoing, there is demand for development of a device for predicting drug responsiveness to specify an effective anticancer agent accurately prior to administration in order to secure safety and attain effectiveness.
Conventionally, a method which comprises contacting various anticancer agents with cancer cells or cancer tissues isolated from a patient, and on the basis of growth suppression etc. of the cancer cells as the indicator, specifying an anticancer agent estimated to be effective against the cancer cells has been used in examination of the sensitivity of anticancer agents to cancer. However, there are cases where examination results of such trial-and-error method are not sufficiently indicative of clinical effects. In addition, large amounts of cancer cells or cancer tissues are necessary in the test of anticancer agents, so there is a problem of great burden on patients. Accordingly, there is desire for establishment of a more objective and accurate method for determining the susceptibility of a cancer to anticancer agents.
It has been confirmed that serine-threonine kinase Akt is activated in many cancer tissues. It has also been suggested that Akt is closely related to malignant transformation. Activation of Akt requires phosphorylation. Activated Akt promotes phosphorylation of molecules involved in suppression of cell death. Cellular apotosis is thereby suppressed and cellular malignant transformation is caused. It is reported that patients with overexpression of activated Akt, as compared with those with underexpression of activated Akt, are generally at an increased risk for worse progress after operation and for adverse prognosis (Cicenas et al., Breast Cancer Research, Vol. 7, No. 3, pp. 394-401 (2005)). Generally, chemotherapy with anticancer agents is poor in efficacy for adverse-prognosis cancer. Accordingly, adverse-prognosis cancer is hardly treated. As a result, a patient with adverse-prognosis cancer is at high risk for cancer recurrence.
An anthracycline anticancer agent is an anticancer agent which inhibits recombination of DNA for topoisomerase II, thereby inducing apotosis. The anthracycline anticancer agent is clinically highly valued. Particularly, it is widely used in chemotherapy for breast cancer. However, the anthracycline anticancer agent, similar to other anticancer agents, might cause significant side effects such as cardiac toxicity and reduction in white blood cell. Accordingly, it is very important to establish an objective and accurate method for determining the susceptibility of cancers to the anthracycline anticancer agent.